Phosphorus containing reaction products

ABSTRACT

Reaction products of phosphonic acid esters, an aliphatic alcohol and optionally an epoxide are provided which are useful as flameproofing agents. In particular soft polyurethane foams are rendered inflammable.

United States Patent [191 Hofmann et al.

PHOSPHORUS CONTAINING REACTION PRODUCTS Inventors: Peter Hofmann; Peter Rohringer,

both of Basel, Switzerland Assignee: Ciba-Geigy Corporation, Ardsley,

Filed: Dec. 1, 1972 Appl. No.: 311,052

Related U.S. Application Data Continuation-impart of Ser. No. 266,194, June 26, 1972, abandoned.

Foreign Application Priority Data June 3, 1975 [58] Field of Search 260/920, 929, 953, 982

[56] References Cited UNITED STATES PATENTS 2,875,230 2/1959 Coover et al. 260/982 3,138,629 6/1964 Laughlin 260/982 3,294,873 12/1966 Lutz et al 260/929 Primary ExaminerLorraine A. Weinberger Assistant ExaminerRichard L. Raymond Attorney, Agent, or F irm-Prabodh I. Almaula; Luther A. R. Hall [5 7] ABSTRACT Reaction products of phosphonic acid esters, an aliphatic alcohol and optionally an epoxicle are provided which are useful as flameproofing agents. In particular soft polyurethane foams are rendered inflammable.

9 Claims, No Drawings puosrnorws CONTAINING REACTION PRODUCTS RELA ED APPLICATION This application is a'continuation in part of copending application Ser. No. 266,194 filed June 26, 1972 now abandoned.

The subject of the invention is a reaction product of l. a phosphonic acid ester of the formula wherein R has the indicated meaning, which is liberated during the reaction, being at least C below the boiling point of the alcohol XOH, and

3. optionally, an epoxide with 2 to 4 carbon atoms.

The radicals R and R in the formulae l and (3) are different from one another, or, preferably, identical with one another. These alkyl radicals are, for example, n-butyl, isopropyl, n-propyl, ethyl or, preferably, methyl.

Preferably, methanephosphonic acid dimethyl ester is used as component (1) in the process according to the invention.

The radical X in the formula (2) is derived from monohydric or polyhydric alkanols, for example from stearyl alcohol, lauryl alcohol, n-octanol, n-hexanol, n-, 1- or Z-butanol; polyols, such as glycerine or, preferably, diols such as ethylene glycol, 1,2-n-propanediol, 1,4-n-butanediol or l,5-n-pentanediol; or halogenoalkanols, for example 1,2-dibromopropanol, chlorohydrin or trichloroethanol; halogen here as a rule denotes iodine or especially bromine or chlorine.

Where the alcohol of the formula (2) is a polyol, reaction products which contain more than one radical, for example 2 to 6, preferably 2, radicals of the formula (2), can be obtained.

Preferably, an alcohol of the formula (4) X,OH wherein X denotes alkyl with 3 to 22, preferably 3 to 5, carbon atoms or hydroxyalkyl with 2 to 6 carbon atoms, isused for the manufacture of the products employed according to the invention.

, Further alcohols which are suitable are above all :fthoseof the. formula 2(5)] wherein X- d enote s hydroxyalkyl, preferably monohyhydroxides. As such it is possible to use, for example, Na O, K 0, SrO, BaO, Mg(OH) or Ca(OH) or above all MgO and especially CaO. The oxides can also be employed as mixtures, optionally also mixed with other metal oxides such as, for example, lead-II oxide. Where the components (1 are pure products, free of dimethyl phosphite or trimethyl phosphite, the reaction products can also be manufactured in the presence of acid catalysts such as p-toluenesulphonic acid, MgCl ZnCl H2804, H3PO4 Or The trans-esterification is appropriately carried out at temperatures of to 220C, preferably -200C or especially to C.

The molar ratio of the starting components can vary within wide limits but is generally, depending on the functionality of the alcohol, 6:1 to 1:3, preferably 2:1 to 1:3 (phosphonic acid ester alcohol). The transesterification is particularly advantageously carried out with 1-2 mols of phosphonic acid ester and 1 mol of alcohol and 0 to 1 mol of epoxide.

The optionally conjointly used component (3) is, for example, 1,2-butylene oxide or preferably ethylene oxide or especially l,2'-propylene oxide.

The reaction products used according to the invention are complex mixtures of products of differing composition. In addition to smaller proportions of starting product, these mixtures contain products which probably, for example in the case where methanephosphonic acid dimethyl ester, glycerine and 1,2-propylene oxide are used as the starting products, for example correspond to the following formulae:

Analogous mixtures are obtained on using other starting products.

These reaction products are used for flameproofing plastics.

Suitable plastics for flameproofing are, for example, viscose, with the reaction products being added to the spinning composition, or above all polyurethanes, preferably polyurethanefoams or coatings. In particular, soft polyurethane foams are suitable for being rendered of low inflammability according to the process of the invention.

The reaction products are appropriately incorporated into the polyurethane foams or coatings by adding them to the mixture for the manufacture of the foams, or adding them to the coating compositions.

These manufacturing mixtures have the composition which is customary for the manufacture of polyurethane foams. They contain, as a rule, polyesters or polyethers having free hydroxyl groups and a molecular weight of 400 to 6,000, for example polyols and diisocyanates, such as, for example, 4,4'-diphenylmethanediisocyanate or toluylenediisocyanate, as the reactants. As blowing agents required for foam formation, the mixtures contain, for example, fluorotrichloromethane or difluorodichloromethane. As an activating additive the mixtures can furthermore contain a tertiary amine, such as, for example.diaminobicyclooctane. As further activating additives, \the mixtures can contain metal salts, such as, for example,,tin octoate.

Appropriately, l to 15%, preferably 5 to of the flameproofing component containing phosphorus are used relativeto the solids content of the reaction mixtures for the manufacture of polyurethane foam.

The. phosphorus compounds incorporated into the polyurethane-foams give extremely flameproof foams. Furthermore, additions of such phosphorus compounds hardly interfere with the manufacturing process of the foams.

In part, the present phosphorus compounds admittedly have an activating or retarding effect on the course of the reaction of polyurethane formation, but this influence can be controlled by appropriate choice of the amount of blowing agents and activators added. The mechanical properties are also not influenced significantly by the addition of the phosphorus compounds, in that practically no distortion occurs.

This process can be used for flameproofing so-called rigid and soft polyurethane foams. The process is also used for flameproofing polyurethane coatings on fibrous substrates.

Because of the low acidity of the reaction products, the process according to the invention is above all suitable for flameproofing so-called soft polyurethane foam, since in the case of this foam acid products interfere with the reaction of foam formation even more than in the case of rigid polyurethane foam.

Polyols with hydroxyl numbers of 20 to 100, especially of 40 to 60, are particularly suitable for the manufacture of such soft foams.

Polyesters and especially also polyethers, such as are used in the process according to the invention for the manufacture of the polyurethanes, are described in detail, for example in Kunststoff-l-landbuch (Plastics Handbook), volume Vl, Polyurethanes, Carl Hanser Verlag Munich 1966.

It is particularly advantageous to employ halogenfree reaction products in the process according to the invention, since they do not evolve any hydrogen halide gases on combustion.

In the examples which follow, percentages are percentages by weight.

EXAMPLES FOR MANUFACTURE A. 77 g (1 mol) of 1,2-n-propanediol and 124 g (1 mol) of methanephosphonic acid dimethyl ester are treated with 3.7 g (0;O5, mol of calcium hydroxide. Thereafter, 32 g (1 mol) of methanol are distilled off over the course of 1 hour at'l75C. The residue obtained consists of 169 g of a product which probably contains substantial proportions of products of the formula H0 c.-: CH2-O C113 1! 0 0 3 (Bl HO .ci-i on 0 CH 0 o on a 0 0 v 0, O--CH (1i) H,)( O- CH- CH3 B. 920 g (10 mols) of glycerine and 2,480 g (20 mols) of 99% strength methanephosphonic acid dimethyl ester are treated with 56 g (1 mol) of calcium oxide. Thereafter 504 g of distillate of boiling point 45-65C are distilled off over the course of 4-5 hours at a bath temperature of 160l70C and an internal temperature of l55l 60C in the flask. The analysis of the distillate shows 90.7%, corresponding to 14.3 mol of methanol. i l

1n the residue, 0.43 mol of l-l per-mol of phosphorus are found by acidimetric titration. 1

574g mols) of propylene oxideare added dropwise to the 2,952 g of residue and the whole is heated under reflux at C for 4hours. Thereafter, 49 g of unreacted propylene oxide are distilled off, amounting to a consumption of 525 g (9 mols) of propylene oxide.

The acidimetric titration shows 0.07 mol of H per mol of phosphorus.

Viscosity: 506 cSt.

C. 92 g (1 mol) of glycerine (anhydrous) and 248 g (2 mols) of 99% strength methanephosphonic acid dimethyl ester are treated with 5.6 g (0.1 mol) of calcium oxide. Thereafter, 25 g of distillate of boiling point 30-66C are distilled off over the course of 45 hours at a bath temperature of l70l75C-and an internal temperature of 155160C in the flask. The analysis of the distillate shows 98.9%, corresponding to 0.77 mol of methanol.

0.37 mol of l-l per mol of phosphorus are determined in the residueby acidimetric titration.

The total residue from the trans-esteriflcation is esterified with 52.5 g (0.91 mol) of propylene oxide at 707 6C for 6 hours. The acid content of the product is 0.05 mol of H* per mol of phosphorus and the phosphorus content is 19.1%.

Viscosity: 782 cSt.

D. 950 g (10 mols) of glycerine are rendered anhydrous by azeotropic distillation with 200 g of xylene. Thereafter, 2,480 g mols) of dimethylmethanephosphonate (96% strength) and 56 g (1 mol) of calcium oxide are added. The transesteriflcation takes place at 170C for 4 hours, in the course of which 1,014 g of distillate distil off.

The resulting product contains 0.32 mol of H per mol of phosphorus.

518 g of propylene oxide are added dropwise to 1,307 g of the residue and the mixture is heated under reflux at 80C for 4 hours. The resulting product contains 0.02 mol of H per mol of phosphorus.

Viscosity: 25,000 cSt.

800 g of trans-esterified product are heated to 90C and alkylene oxide is then injected. 1n the course thereof, the temperature rises to 105C; after 4 hours, the reaction is complete and 123 g of ethylene oxide have been absorbed. The resulting product contains 0.005 mol of 11* per mol of phosphorus.

Viscosity: 13,000 cSt.

E. 166 g (1 mol) of diethylethanephosphonate and 46 g (0.5 mol) of glycerine together with 8.6 g (0.05 mol) of p-toluenesulphonic acid are trans-esterified for 3 hours at'a bath temperature of 185C and an internal temperature of 175C in the flask. The amount of distillate is 27 g and the acid content in the residue is 0.905 mol of H per mol of phosphorus.

The residue is esterifled with 100 g of propylene oxide at 80C for 4 hours.

The viscosity of the product is 51 cSt. I

F. 256 g (1 mol) of stearyl alcohol and 257 g (2 mols) of methanephosphonic acid dimethyl ester (96% strength) are treated with 5.6 g (0.1 mol) of calcium oxide. Thereafter, 27.5 g of distillate of boiling point 628 1C are distilled off over the course of 3 hours at a bath temperature of 185C and an internal temperature of 170-175C in the flask. g

0.4 mol of H per mol of phosphorus are determined in the residue by acidimetric titration.

The residue is esterified with 366g (0.63 mol) of propylene oxide. The amount ofthe resulting product is 547 g and the acid content is 0.004 mol of H per mol of phosphorus.

G. 465 g (7.5.rnols) of distilled, anhydrous ethylene glycol and 2580 g (20;rnols) of methanephosphonic acid dimethyl ester (96.3%) are treated with 56 g (1 mol) of calcium oxide. Thereafter at a bath temperature of 160C, 470 g of a product having a boiling range of 60 to C under normal pressure and 1 174 g of a product having a boiling range of to C at 14 mm Hg are distilled off. The residue is homogeneous and very acid, it contains 1.4 10' mol of l-l per g.

1092 g of the residue then are reacted with 180 g of propylene oxide at 75C. This product contains only 2.4 10' mol of l-I per g.

EXAMPLES FOR APPLICATION Example 1 A mixture of 20 g of a polyol which reacts slowly (a polyether of molecular weight about 1,000, from trimethylolpropane and propylene oxide), 8 g of fluorotrichloromethane, 21.8 g of 4,4- diphenylmethanediisocyanate, 0.2 g of an activator based on an amine and 5 g of the product according to Instruction A is stirred for 1 minute with a simple paddle stirrer at 1,000 revolutions per minute. Thereafter the mass which is foaming up is immediately introduced into a tube of 5.5 cm diameter and the reaction is allowed to go to completion in the tube, this requiring 10 hours. A foam without addition of product according to Example 1 is manufactured simultaneously. Test of Flameproof Character One specimen at a time, of size 120 X 30 X 10 mm, is fixed with the 120 mm edge at an angle of 45 to the horizontal and the 30 mm edge horizontal.

Marks are made at 25 and 100 mm. The samples are ignited at the lower end for 5 seconds by means of a fishtail burner. The following values are found:

A soft foam is manufactured by mixing the following materials: 100 g of a polyhydroxy compound of a polyether, of molecular weight about 3,000 (manufactured from trimethylolpropane), suitable for the formation of a soft polyurethane foam, 1 g of siloxane-oxyalkylene copolymer, 0.32 g of tin-ll octoate, 3.5 g of water, 48.2 g of toluylene-diisocyanate (80 20 mixture of 2,4/2,6 isomer) and 10 g of flameproofing agent.

ASTM D 1692 Test Method One test specimen at a time, of size 150 X 50 X 13 mm, is fixed with the 50 mm X 13 mm edge horizontal. Marks are made at 25 and 100 mm. The sample is then ignited at the lower end by means of a fishtail burner.

The ignition time is 60 seconds. If the burnt zone is not longer than 25 mm, the foam is described as noninflammable.

If the sample burns beyond the 25 mm mark and the burnt zone is smaller than mm, the foam is described as selfextinguishing. The length of the burnt zone is quoted in centimetres.

If the sample burns beyond the 125 mm mark, the foam is described as inflammable and the speed of burning is quoted.

TABLE wherein R and R each denotes alkyl with 1 to 4 carbon atoms,

2. an alcohol of the formula Product according to Instruction Without additive Elementary analysis: '/r of phosphorus Hydroxyl number:

Flameproofing action.

1. Sheets: of polyurethane. glassfibrereinforced, approx. 220 g/m Limiting oxygen index.

Difference between absence of additive and presence o13()/( of product. X

1.8 mm/sec B C D E F After 1 day 5 cm 5 cm 10 cm 5 cm 5.5 cm

2 days 4 cm 6 cm 4.5 cm 4.5 cm 6 cm 4 days 9 cm 4.5 cm 4 cm 8 cm 4.5 cm

Additionally, the flameproof character was tested after 7 days ageing in the case of two samples:

B: 4 cm C: 6.5 cm.

Example 3 In the same manner as indicated in Example 2 a poly urethane foam is manufactured and tested according to ASTM D-l692 test method:

Amount of flameproofing agent G in of the polyol 10 Cream time 10 seconds Rising time 12 seconds Crosslinking time 3 minutes Burnt zone after 1 day at 140C. 5 cm 2 days at 140C. 5 cm 4 days at 140C. 5 cm We claim:

1. Reaction product of l. a phosphonic acid ester of the formula wherein X denotes monohydroxyalkyl or dihydroxyalkyl with 2 to 6 carbon atoms, with the boiling point of the alcohol of the formula wherein R has the indicated meaning, which is liberated during the reaction, being at least 30C below the boiling point of the alcohol XOH and 3. an epoxide with 2 to 4 carbon atoms in the presence of an alkali metal oxide, alkaline earth metal oxide or alkaline earth metal hydroxide.

2. Reaction product according to claim 1, which comprises as component (1) methanephosphonic acid dimethyl ester.

3. Reaction product according to claim 1, which comprises as component (2) ethylene glycol, 1,2- propanediol or glycerine.

4. Reaction product according to claim 1, which comprises as component (3) ethylene oxide or propylene oxide.

5. Reaction product according to claim 1, manufactured at to 220C.

6. Reaction product according to claim 1, in the manufacture of which (1) the phosphonic acid ester and (2) the alcohol are reacted with one another in a molar ratio of 2: 1 to 1 :3.

7. Reaction product according to claim 1, of l to 3 mols of the component l and 1 mol of the component (2) and 0.63 to 1 mol of the component (3).

8. Reaction product according to claim 1 of l. methanephosphonic acid dimethyl ester 2. glycerine and 3. ethylene oxide 9. Reaction product according to claim 1, of

l. methanephosphonic acid dimethyl ester 2. ethylene glycol 

1. REACTION PRODUCT OF
 1. A PHOSPHONIC ACID ESTER OF THE FORMULA
 1. methanephosphonic acid dimethyl ester
 1. a phosphonic acid ester of the formula
 1. Reaction product of
 1. methanephosphonic acid dimethyl ester
 2. glycerine and
 2. an alcohol of the formula X-OH wherein X denotes monohydroxyalkyl or dihydroxyalkyl with 2 to 6 carbon atoms, with the boiling point of the alcohol of the formula R-OH wherein R has the indicated meaning, which is liberated during the reaction, being at least 30*C below the boiling point of the alcohol X-OH and
 2. AN ALCOHOL OF THE FORMULA
 2. Reaction product according to claim 1, which comprises as component (1) methanephosphonic acid dimethyl ester.
 2. ethylene glycol
 3. Reaction product according to claim 1, which comprises as component (2) ethylene glycol, 1,2-propanediol or glycerine.
 3. an epoxide with 2 to 4 carbon atoms in the presence of an alkali metal oxide, alkaline earth metal oxide or alkaline earth metal hydroxide.
 3. propylene oxide.
 3. AN EPOXIDE WITH 2 TO 4 CARBON ATOMS IN THE PRESENCE OF AN ALKALI METAL OXIDE, ALKALINE EARTH METAL OXIDE OR ALKALINE EARTH METAL HYDROXIDE.
 3. ethylene oxide
 4. Reaction product according to claim 1, which comprises as component (3) ethylene oxide or propylene oxide.
 5. Reaction product according to claim 1, manufactured at 95* to 220*C.
 6. Reaction product according to claim 1, in the manufacture of which (1) the phosphonic acid ester and (2) the alcohol are reacted with one another in a molar ratio of 2: 1 to 1 :
 3. 7. Reaction product according to claim 1, of 1 to 3 mols of the component (1) and 1 mol of the component (2) and 0.63 to 1 mol of the component (3).
 8. Reaction product according to claim 1 of 